iCal Reminder Has Wrong Time

When I create an event in iCal that occurs, for example, at 5:30 PM with a reminder for one day before the event at the same time, the reminder pops up at 8:30 PM (with that time in the reminder window). I recently moved from the west coast to the east coast and changed my time zone in the System Preferences. Somehow, iCal still thinks I an in the Pacific time zone, and the reminders are popping up 3 hours later that they should. Any ideas on how to fix this?